The funny thing was, I hadn\u2019t even done the race. As a young staff writer for Triathlete, I had spent the day on the back of a press truck tracking the women\u2019s pro field. But this effort alone was enough to leave me wrecked for the next 24 hours. I might not have burned many calories on that flatbed, but it\u2019s the elements that get you in Kona \u2014 the simmering lava fields<\/a>, the glaring sun, and those dreaded mumuku winds \u2014 and they got me despite my low step count.<\/p>\n Completing an Ironman anywhere is hard. Simply watching an Ironman in Kona is also hard. At the Ironman World Championship<\/a>, prolonged physical exertion and a harsh environment combine to produce a post-race hangover like no other.<\/p>\n But what\u2019s actually happening inside your body after Kona that makes you feel so utterly steamrolled? In an effort to answer this question, I scoured the research journals and interviewed experts in medicine, neuroscience<\/a>, and psychology. What follows is a short list of things you might hear yourself say on \u201cRecovery Sunday\u201d in Kona, and the science behind them.<\/p>\n \u201cMy legs feel like they\u2019ve been used as pi\u00f1atas.\u201d<\/p>\n Crossing the finish line on Ali\u2019i Drive is an emotional experience, but when that initial rush of euphoria wears off, the strongest sensation you\u2019re left with is leg pain. And where there\u2019s pain, there\u2019s harm.<\/p>\n \u201cWhen you put your body through that kind of test,\u201d says Jeff Sankoff, MD<\/a>, an emergency medicine specialist, triathlon coach, and Triathlete contributor<\/a>, \u201cyou have microscopic breakdown of muscle fibers.\u201d<\/p>\n But that\u2019s only the beginning. \u201cThe muscle damage that occurs results in leakage of things that should not be in the serum and the surrounding tissues,\u201d Sankoff continues, noting that the effect is especially pronounced in hot environments like Kona\u2019s. Creatine kinase, myoglobin, and other cellular waste products accumulate around damaged muscle fibers, triggering an inflammatory response that stimulates pain receptors. That\u2019s why your legs hurt<\/a> even more the next morning, and why the phenomenon Sankoff is describing is known as delayed-onset muscle soreness<\/a> (or DOMS).<\/p>\n Except in extreme cases, the muscle pain<\/a> you experience after Kona and similar events is nothing to worry about and will disappear within a few days. Sankoff recommends gentle activities \u2014 a casual stroll or a gentle swim or spin \u2014 as the best ways to take the edge off your discomfort on Recovery Sunday.<\/p>\n \u201cMy knees won\u2019t bend.\u201d Closely related to DOMS is joint stiffness<\/a>. According to Sankoff, \u201cThe same inflammatory response that causes muscle soreness also creates fluid buildup, so you get localized swelling in the muscles and joints.\u201d The resulting pressure acts like a liquid brace around your ankles, knees, hips, and shoulders, restricting movement. Try not to drop your room key on Recovery Sunday, because you\u2019ll have a heck of a time picking it up!<\/p>\n \u201cI have zero energy. None.\u201d<\/p>\n Nobody is surprised when they feel tired after a long-distance triathlon<\/a>. The typical athlete burns 8,000 to 10,000 calories during an Ironman while consuming 3,000 to 4,000 calories, leaving them with a sizable deficit when it\u2019s over. Even if you manage to eat a big dinner that night (which isn\u2019t likely, for reasons we\u2019ll get into), you\u2019re still going to wake up the next morning with a depleted body battery, and you\u2019ll feel it.<\/p>\n Here again, Kona\u2019s sauna-like conditions compound the issue. Research has shown that the body\u2019s efforts to maintain a stable core temperature on a sultry day increase the energy cost of exercise. A 2024 study<\/a> published in the journal Temperature found that soldiers burned 11% more carbohydrate when rucking in a hot environment (98 degrees F) than they did at the same speed in temperate surroundings (68 degrees F).<\/p>\n To keep from overheating, your body sweats, which leads to dehydration<\/a>, which also causes tiredness. You\u2019re likely to lose 2 to 3% of your body mass<\/a> through perspiration in the course of completing an Ironman, perhaps more on the Big Island. On top of that, ultraviolet radiation makes you tired even on a cool day by causing skin damage that requires energy to repair. Add it all up, and it\u2019s no wonder you have zero energy on Recovery Sunday.<\/p>\n \u201cI feel like I\u2019m wearing cement boots.\u201d<\/p>\n If you\u2019re like most triathletes, you think of fatigue<\/a> as something that happens in your muscles, and it does. But in long events like the Ironman World Championship, your nervous system, which drives the muscles, becomes even more fatigued.<\/p>\n \u201cWhen you push yourself for a long period of time,\u201d says Scott Frey, PhD, a neuroscientist at Cerebral Performance<\/a>, \u201cthe motor system in the brain slowly loses its capacity to drive output.\u201d Electrical signals sent from the brain to the limbs get measurably weaker, and performance declines. In one study<\/a>, athletes completed a jumping test before and after a long-distance triathlon to assess neuromuscular fatigue. As expected, they lost some of their hops post-race, but the primary cause wasn\u2019t muscle fatigue per se but reduced input to the muscles from a worn-out brain.<\/p>\n If you race in Kona, you know better than to test your jumping ability soon after the event. Yet even if you do nothing more strenuous the next day than stroll around town, you\u2019ll likely feel sluggish, heavy \u2014 and clumsy. According to Frey, dexterity and coordination are also compromised when your nervous system is fried. Playing darts may not be the best way to celebrate a successful finish at the Ironman World Championship.<\/p>\n \u201cI can\u2019t string two thoughts together.\u201d When you participate in events like the Ironman World Championship, your nervous system operates in a state of sympathetic activation, marked by high levels of cortisol<\/a>, norepinephrine, and other stress-related hormones and neurotransmitters. You need sympathetic activation to stay focused, tolerate pain<\/a>, and get the most out of your muscles on the racecourse, but it takes a toll on the brain. Studies show<\/a> that activity in the prefrontal cortex, the command center of the brain, is reduced in the recovery period after long races like Kona, and it\u2019s something you notice.<\/p>\n \u201cWhen people are in these acute recovery states,\u201d Frey says, \u201cthey have issues with what we call executive function<\/a> or cognitive control. Difficulty making decisions. Brain fog. Poor impulse control.\u201d In another day or two, your gray matter will be back to normal, but think twice before you purchase a timeshare on Recovery Sunday.<\/p>\n \u201cI could eat an entire lasagna \u2013 and I don\u2019t even like lasagna!\u201d<\/p>\n In 2002, I completed my first Ironman as an actual participant. That evening I went out to dinner with my family and ordered a mushroom bacon cheeseburger with duck fat French fries. When the food came, I ate two bites and pushed the plate away, not because I didn\u2019t like it but because my stomach wasn\u2019t ready. The following morning, I devoured a three-egg farmer\u2019s omelet with toast and hash browns and couldn\u2019t wait for lunch.<\/p>\n This is normal, experts say. \u201cYou\u2019ve diverted blood away from your gut all day long,\u201d Sankoff explains, \u201cand it sustains an injury. Your gut is not able to suddenly handle food right away, especially foods high in fat and protein, which delay gastric emptying<\/a>.\u201d\u00a0 And in case you were wondering, yes: Heat and humidity<\/a> exacerbate the problem, making the Ironman World Championship especially hard on the GI system.<\/p>\n Hormonal shifts also contribute to the \u201cno, thanks\u201d feeling you get in the first few hours after an Ironman. GLP-1 \u2014 the now-famous satiety peptide \u2014 spikes, while ghrelin \u2014 a hunger hormone \u2014 drops. By the time you wake up, however, your GLP-1 will be down, your ghrelin up, and you just might be in the mood for a hearty breakfast.<\/p>\n \u201cJust go with the flow\u201d is Sankoff\u2019s advice. \u201cWhen your body\u2019s ready to start making up that calorie deficit, it will tell you.\u201d Obeying your hunger is just about the best thing you can do to boost your recovery the day after an Ironman, Sankoff adds, supplying nutrients vital to replenishing muscle and liver glycogen, repairing muscle damage, and getting your body back to homeostasis.<\/p>\n \u201cI think I might be coming down with something.\u201d<\/p>\n Odds are you won\u2019t get sick while you\u2019re in Kona, but you might. A 2024 meta-analysis<\/a> appearing in Exercise Immunology Reviews found that the risk of catching a virus rose by 18% in the days following a marathon. Post-Ironman sickness rates have not been studied, but it\u2019s a safe bet they\u2019re comparably elevated.<\/p>\n Scientists aren\u2019t exactly sure why endurance races like the Ironman World Championship open the door to infection. The leading theory is that these extreme efforts deprive immune cells of the energy needed to do their job properly. Environmental factors may also be at play. Being surrounded for several hours by dozens of sweat-basted, mouth-breathing competitors seems like a pretty good way to pick up whatever\u2019s going around.<\/p>\n I don\u2019t mean to alarm you. Doctors like Sankoff don\u2019t see viral risks as a reason to avoid Kona or other big events as long as you\u2019re healthy going into them. To reduce your chances of feeling under the weather on Recovery Sunday, avoid unnecessary social contact, wash your hands frequently, and mask up for extra protection.<\/p>\n \u201cI can\u2019t remember the last time I felt so [fill in the blank].\u201d<\/p>\n The physical effects of racing in Kona are highly predictable. Everybody is tired and sore the next day. The psychological effects, however, are harder to anticipate.<\/p>\n \u201cThere is no correct way to feel after a big event like an Ironman,\u201d says mental performance consultant Carrie Jackson<\/a>, who has seen everything from towering euphoria to deep despondency in her clients after important races. \u201cIt totally depends on the person and the experience.\u201d Proud, angry, grateful, regretful, empty \u2014 however you feel on recovery Sunday, Jackson assures, your emotions are probably normal and definitely temporary.<\/p>\n A variety of factors feed into the emotions you experience in the wake of a major competition. On the physical side, it\u2019s been shown that brain fatigue impairs emotional regulation<\/a>, which can bring about what Jackson refers to as \u201cemotional flooding,\u201d where you feel as though you might cry or laugh at any moment without knowing why.<\/p>\n On the mental side, a phenomenon called event centrality plays a role in shaping post-race emotions. \u201cWhether it\u2019s a wedding or an Ironman or some other event,\u201d Jackson says, \u201cwhen you spend a long time putting a lot of energy into planning and preparing for one important day, it gives you forward momentum and a sense of purpose, and when suddenly it\u2019s over, it\u2019s like now what?\u201d<\/p>\n Some athletes discover a sense of relief in the vacuum that opens up after a big race, while others experience a kind of grief<\/a>. The biggest races produce the strongest emotional aftershocks, and there\u2019s no race bigger than the Ironman World Championship. Jackson teaches her clients to accept that strong emotions, including negative feelings, are as natural as muscle soreness<\/a> and other physical effects. Observe them without judgment and you\u2019ll feel better than you will by fighting your emotions.<\/p>\n Totally worth it<\/p>\n Earlier this year, Sankoff attended an awards ceremony at Ironman Kalmar-Sweden, where he watched second-place men\u2019s finisher Matthew Marquardt<\/a> struggle to climb the podium on shaky legs. \u201cIt made me realize that even guys like him,\u201d he told me, \u201cwho are so supremely trained, put their bodies through that test and have stiffness and soreness just like the rest of us.\u201d<\/p>\n
\n![\"An](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/10\/Hannah-DeWitt_Triathlete-scaled.jpeg\"\/)
(Photo: Hannah DeWitt\/Triathlete)<\/p>\n
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(Photo: Hannah DeWitt\/Triathlete)<\/p>\n